package com.lfk.api.config;


import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;


/**
 * <p>
 *  Redis锁
 * </p>
 *
 * @author Cat凯
 * @since 2023-2-1
 */
public class SimpleRedisLock implements ILock{

    private String name;
    private StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static final String KEY_PREFIX="lock:";
    private static final String ID_PREFIX= UUID.randomUUID().toString(true)+"-";
    //提前读取lua脚本
    private static final DefaultRedisScript<Long>UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT=new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取线程标识
        String threadId=ID_PREFIX+Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX+name, threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);//避免自动拆箱风险
    }

    @Override
    public void unlock(){
        //调用lua脚本
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX+name),//生成单元素的集合
                ID_PREFIX+Thread.currentThread().getId());
    }

//    @Override
//    public void unlock() {
//        //获取线程标识
//        String threadId=ID_PREFIX+Thread.currentThread().getId();
//        //获取锁中标识
//        String id=stringRedisTemplate.opsForValue().get(KEY_PREFIX+name);
//        //判断标识是否一致
//        if(threadId.equals(id)) {
//            //释放锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//    }
}
